The object of the invention is a variable-capacity buffer store for rod-shaped articles designed particularly for storing cigarettes supplied from a production machine and transferring cigarettes to a receiving machine e.g. packing machine. This store is used for compensating the differences between the work speed of those two cooperating machines.
The known modern production lines for the production and the packing of cigarettes comprises, the production machine or set of machines for the production of cigarettes and the packing machines or set of packing machines, to compensate for the unequal efficiency of both mentioned machines, the different storing apparatus are used in the production lines situated between the production machine and the packing machine. Due to technological reasons, most suitable store apparatus work in the system first in first out. This system eliminates drawbacks, which exist in the system first in, last out, where the cigarettes can stay in the store for a long time. Moreover, due to the enormous work speed, efficiency reaches 14,000 cigarettes per minute. Then, every break or slow down in one of the machines in the line forces the use of the compensating buffer store apparatus with large capacity. Only a variablecapacity store with an endless conveyor can be used, because the area assigned for the cigarette production line is limited. From the description of German patent DE 4.224.609, one known variablecapacity store working on the first in, first out system, comprises a transportation device for multilayered streams of cigarettes, transported along a helical track. The store consists of a first and second transportation section connected in series from the input station to the output station, which is situated at the ends of the mentioned helical track. The first and second transportation section is combined together by the deflecting device which drives both sections in that way, to change properly, the length of the transportation section occupied by the cigarettes, which results in a change in the capacity of the store. In the described variablecapacity store, in the place where the first section combines with the second section, transported by the deflecting device, the cigarettes are constantly pressed by the mentioned deflecting device, which can damage them. Another construction of the variable-capacity store for elongated elements, in particular tobacco products working on the first in, first out system, is known from the description of the European patent application EP.738.478. The mentioned store comprises the input station and the output station located in series, along the trajectory, along which the elongated articles are transported, and also the conveying means, with the variable length for transporting those elements, situated between the input station and the output station. The mentioned conveying means, comprises the endless conveyor, situated in the transport sector, where the elongated elements are stored and in the return sector where the conveyor is empty. The conveyor lengths in the sectors are variable and compensate each other in a manner that the total conveyor length is constant. The transport sector is located between the input station and the output station, the return sector is located between the output station and the input station. Moreover the store consists of the devices for changing the conveyor length in every sector in a manner that their length compensate each other. These devices have the first drive means connected to the transport sector, which can regulate the conveyor length of the first spiral in defined changes in that sector and the second drive means connected to the return sector which can regulate the conveyor length of the second spiral in defined changes in that sector. Equally the first spiral in the transport sector and the second spiral in the return sector are supported by the drums where, at least one in every sector can change their position being driven by the motor, which is the part of said variable devices for varying the conveyor length in every sector. The first and second spiral is wound on the proper assembly of the two drums, leaving identical distances between the curvatures or in different distances for every sector. The conveyor spirals of both sectors are situated beside, or the second conveyor spiral of the return sector is situated inside the first spiral of the transport sector. This solution demands very complicated, in respect to the regulation means, which are also mechanical, devices for changing the conveyor length in both sections, by which it is possible to obtain the proper change of length of the spiral in every sector after the signal is received from the sensor situated at the output of the cigarette production machine, and the input of the packing machine. Moreover the store depicted in the description and figures will be difficult to realise in respect to significant friction between the conveyor and drums, specially under the full load of the conveyor in the transport sector.
An object of the invention is the construction of the variable-capacity buffer store for rod-shaped articles working on the first in, first out system, having the input station cooperating with the production machine and the output station cooperating with the receiving machine. The stations cooperate with an continuous endless conveyor for transporting the rod-shaped elements from the input station to the output station and the first part of which is situated in the transport sector between the input station and the output station and the second part of which is situated in the return sector and by the way the length of the conveyor in sectors compensates for each other. At the inlet of the transport sector is situated the first drive means of the conveyor, which is controlled by and connected to a fullness sensor assembled in the input station via a control unit, and at the exit of the transport sector is situated a second drive means of the conveyor which is controlled by and connected to a fullness sensor assembled in the output station via a control unit. The transport sector is determined by the two, active and passive, identical support guide means of the conveyor that consist of the independent disc modules rotary assembled on the axes, and the return sector is determined by the two, active and passive, identical support guide means of the conveyor that consist of the independent disc modules rotary assembled on the axes, and by the way, the axis of the active support guide means in the transport sector is fixed to the axis of the active support guide means in the return sector by a carriage moveably assembled on a horizontal guide bar on a frame of the store in a plane perpendicular to the axes. Equally in the transport sector and in the return sector, the disc modules are assembled at an angle to the axes of the support guide means, in a manner that, the planes of the disc modules in every support guide means are parallel to each other. The axes of all support guide means in the transport sector and in the return sector are situated beneficially in the one vertical plane. At the maximum capacity of the store, the axis of the active support guide means in the transport sector is the continuation of the axis of the passive support guide means in the return sector, and at the minimum capacity of the store, the axis of the passive support guide means in the transport sector is the continuation of the axis of the active support guide means in the return sector. The axes of the support guide means in the transport sector can be situated in the vertical plane, which is parallel to the plane defined by the axes of the support guide means in the return sector. Below the conveyor in the transport and return sector in the zone of action of the support guide means, are assembled to the frame, the horizontal guide bars supporting the conveyor. Moreover the store is equipped with a tensioning device for the conveyor. The input station and the output station are situated beneficially perpendicularly to the conveyor trajectory. This construction of the store enables temporary gathering of the rod-shaped elements in the transport sector in the form of continuous multilayer stream on the conveyor constructed of the segments and the maximum capacity of the store is defined by the maximum distance between the outer edges of the support guide means in the transport sector and by the amount of the employed disc modules in the support guide means situated there and by the height of the elements stream on the conveyor. The store adapts itself to the expected temporary capacity, and the change of the capacity is done automatically after the differences occur between the conveyor speed in the zones of the output and the input stations and the demanded capacity is retained, by the proper conveyor length which is made by a change of the carriage location, carrying with it the active support guide means, only as a result of the conveyor action cooperating with it and the disc modules of the said means. The linear speed of the conveyor in the input station zone, depends on the amount of the elements incoming from the production machine, and the linear speed of the conveyor in the output station zone, depends on the amount of the elements being received by the packing machine, and these speeds vary in a continuous way. Perpendicular location of the input station and the output station against the conveyor trajectory, enables the location of the production line in a group to form in a considerably small area.